"This is payback," he said into a video camera, vowing to avenge the deaths of Osama bin Laden and Muslims in the Middle East and the Balkans.

"We're coming for your blood, and we're coming for your women's blood and we're coming for your children's blood," he said, an AK-47 propped against the wall behind him.

Unbeknownst to Osmakac, the man on the other end of the camera that day in 2012 was an undercover FBI agent. On Wednesday, he became the first witness to testify in the Kosovo-born, American citizen's terrorism trial, his identity hidden behind a screen and a pseudonym: Agent Amir Jones.

He told the jury how Osmakac had asked him to hold the camera while the man ranted for more than eight minutes, urging violence against non-Muslims in a video that was recorded for posterity but, until the trial, had been largely kept confidential.

Hours after the video was made, Osmakac was arrested in the hotel parking lot and charged with possessing an unregistered AK-47 and attempting to use a weapon of mass destruction. He faces life in prison if convicted.

Using a line of argument common in terrorism cases that rely on undercover federal agents, Osmakac's attorney George Tragos said his client was a zealot and a radical, but without the FBI agent's cajoling, would never have put his thoughts into action. Twenty-five years old at the time of his arrest, Osmakac was a "wild, young, poor, mentally ill person with lower-than-average IQ" who was susceptible to government entrapment, Tragos said.

"This entire case is like a Hollywood script," he said, and the script writers worked for the government.

Tragos noted that his client was broke. To buy weapons from the man he thought was a dealer but was actually an FBI agent, Osmakac leaned on an acquaintance, a man he believed was in his corner. In reality, the man had turned Osmakac in to the FBI and was being paid as an informer. Osmakac was using government money to buy government weapons, Tragos said. The FBI was on "both sides of this transaction."

Prosecutor Sara Sweeney portrayed the now 27-year-old Osmakac as a man bent on killing as many people as possible. To him, everyone was an infidel — the government, law enforcement officials and ordinary American citizens, she said.

Sweeney showed the jury a video Wednesday of Osmakac's first meeting in late 2011 with the undercover agent. In the recording, he orders weapons with the casual manner of a man asking for cream with his coffee. "Ten grenades minimum, if you can," he says. "Maybe a couple of Uzi because they're better to hide."

The agent said Osmakac then gestured to his waist, indicating that he wanted to buy a suicide bomber belt. In a later meeting, he added an item to his order: two or three bombs that he would detonate in rental cars. The agent quoted him a price of $2,500 for the entire arsenal.

Osmakac's plan, Sweeney said, was to park one of the car bombs outside MacDinton's, an Irish bar in South Tampa, and set it off remotely via a cellphone. His next step would be to strap on the belt filled with explosives and head to the Hard Rock Casino, where he planned to shoot patrons and explode the grenades. He wanted to take hostages, Sweeney said, people he could use as bargaining chips to win the freedom of Muslims held in American prisons. He expected that police officers would surround him, and when they did, he would pull the trigger on the explosives strapped to his torso.

He did ultimately acquire a 100-pound car bomb, grenades, an AK-47 and a pistol — all weapons provided by the FBI agent, and none of them in working order, a fact of which Osmakac was unaware.

"You'll see the joy on Mr. Osmakac's face as he gets the guns and the explosives he asked for," Sweeney told the group of 12 jurors and six alternates selected Wednesday.

Throughout his meetings with the undercover agent, all of which were recorded, Osmakac expressed concern that he was under surveillance.

He worried that the FBI was using airplanes and cars to track his movements, and had been ever since he took a trip to the Middle East. He told the agent that he couldn't use the Internet anymore because he was being spied on, and that the government was tapping his phone calls.

While sitting in the agent's car, he asked the man to turn on the radio to drown out their conversation in case anyone was listening.

Classical music filled the car as they discussed how long it would take to make homemade grenades, their every word captured by the FBI.

As the music ended, the radio DJs could be heard announcing the name of the last piece, a Bach arrangement. It was called Sheep May Safely Graze.

Anna M. Phillips can be reached at aphillips@tampabay.com or (813) 226-3354.

Sami Osmakac, 27, is charged with attempting to use a weapon of mass destruction.